schwartz



M. SCHWARTZ.

SELECTIVE RINGING TELEPHONE SYSTEM.

APPLiCATlON FILED JAN425.1912- RENEWED JAN. 4, 191's.

1 ,3 1 2,706. Patented Aug. 12, 1919.

2 SHEETS-SHEET I.

M. SCHWARTZ.-

SELECTIVE RING'ING TELEPHONE SYSTEM.

APPLICATION FILED JAN. 2;: I912. RENEWED JAN. 4. 1919.

1,3 1 2,706. Patented Au 12,1919.

2 SHEETSSHEET 2.

1, (/1 6% QMZQQJ LQHMOQ UNITED srarns PATENT ora ion.

MICHAEL SCHWARTZ, OF CHICAGO, ILLINOIS, ASSIGNOE, 'IO AUTOMATIC ELECTRIC COMPANY, OF CHICAGO, ILLINOIS, A CORPORATION ILLINOIS.

SELECTIVE RINGING TELEPHONE SYSTEM.

Specification of Letters Patent.

Patented Aug. 12, 1919.

Application filed January 25, 1912, Serial No. 673,437. Renewed January 4, 1919-. Serial No. 269,656.

T 0 all whom it may concern Be it known that 1, MICHAEL SCHWARTZ, a citizen of the United States of America, and resident of Chicago, Cook county, Illinois, have invented a certain new and useful Improvement in Selective Ringing Telephone Systems, of which the following is a specification. I

My invention relates to an improvement in party-line telephone systems, and more,

particularly to a telephone system in which automatic switches are employed for establishing a connection between a calling and a called subscribers line, and in which ringing current is applied automatically to a called party-line in order to selectively signal the different stations upon such partyline.

Heretofore, in automatic systems in which it was desired to auton'iatically selectively signal on the called line, two general methods have been employed. In the first of these it was customary to provide each connector switch with an auxiliary switching device called a frequency selector which was operated in response to impulses received from the calling substations to select the particular ringing generator which produced ringing currentof the proper character for signaling the desired substation. This system was objectionable in that it was necessary to employ an extra digit in the numbers of all party-lines in order to transmit the necessary impulses for operating this auxiliary switching device. In the second method each party-line was made accessible through as many groups of connector switches as there were substations on the called line, each group of connectors being accessible through a different level of the selector switches, and each group of connectors being supplied with ringing current of a different character. In such a system each line may be called through any one of a number of groups of connector switches, but if it is called through one group of connectors but one form of ringing current will be impressed upon the called line, While if it is called through a different group of con nectors a different character of ringing cur- 1 rent will be supplied to the line. Thissystcm has the objection that it is inellicient, because the connector switch cannot be used ringing current which is connected to the line being dependent upon the particular level of the selector switch through which connection is established with the connector. By this arrangement it is unnecessary to employ an extra series of impulses to operate the selective mechanism, and. furthermore, any connector may be used to call any of the substations on the lines to which it has access.

These and other objects of my invention .will be more readily understood by reference .to the accompanyingdrawings, 1n wh1ch Figures 1 and 2 taken together show a complete connection between a calling substation-A and :1 called substation A in an automatic telephone system embodying the principles of my invention.

Fig. 3 represents a modification of the connector circuits.

The telephone system in connection with which I have chosen to illustrate my invention is the well-known Strow er system of the so-called two-wire type-t at is, of the type in which the central oflice apparatus is controlled by impulses transmitted from the calling substation over the two sides of the line in series. The connection shown is established through the medium of a subscribers individual or line switch C, a first selector E, a second selector E and a connector H. v

The automatic substations A and A may be of any type of common battery substations provided with an automatic-calling dehowever, the calling device is represented diagrammatically by a. pair of impulse springs 2 and 3 and a toothed impulse wheel 4, which latter is assumed to be controlled by the calling subscriber through the medium of a dial (not shown) provided with finger holes in such a manner that when the calling device is operated to call any digit, the springs 2 and 3 may be momentarily separated to produce a number of breaks in the line circuit, corresponding to the digit called.

The line switch C'and the master switch D are of the general type of line and master switches disclosed in British patent to R. W.

James, No. 26,301 of 1906, but are of the particular type shown and described in British patentto T. G. Martin, No. 1,419

The selectors E and E are of the general type of selector switches shown 1n United States Letters Patent No. 815,321, granted March 13, 1906, to Keith, Erickson and Erickson, being modified, however, as shown in said British Patent No. 1,419 of 1910, so as to operate in the two-wire system shown. The selectors each compromise the usual double-wound line relay 5, the vertical and rotary magnets 6 and 7, private magnet 8, release magnet 9, a slow acting release relay 10, private magnet relay 11, guarding relay l2 and the side switch comprising the wipers 13, 14, 15 and 16.

The connector H (Fig. 2) is of the general type of connector switches disclosed 1n United States Letters Patent No. 815,176, granted March 13, 1906, to Keith, Erickson and Erickson, being essentially the same, however, as the particular form shown in British Patent No. 1,419 of 1910, referred to above. This connector comprises the usual line relay 17 the vertical and rotary magnets 18 and 19, release magnet 20, private magnet 21, ringing relay 22, back-bridge rela 23 and the side switch.

Smce the construction and mode of operation of the central ofiice apparatus are in general well known and fully described in the publications referred to, it is not thought necessary to give a complete description of all the details of operation.

The system shown herein is a party-line system. As shown, the apparatus is adapted to accommodate four substations on each line, only one bein shown, however. All the substations on t e same line are alike, except that the ringers 24 are adapted to respond to difierent kindsofringing current. Any of the well-known means for operating the ringer selectively may be employed, the simplest method being to use ringing current of different frequencies and constructing and adjusting the ringers at the substations-so as to respond to only one frequency. As herein shown, there are provided at the by means of acommon conductor.

central oilice four ringing current generators R, R B and R, the generator R being adapted to operate the ringers of one station on each line, the generator R being adapted to furnish ringing current of the proper character to operate the ringer at a different substation on each line, etc. Each group of party-lines is accessible to only one group of connector switches, this group of connector switches, however, being accessible through four difl'erent levels of the second selectors E. For instance, the first contacts in each of the first four levels of the selector would be connected to a singletrunk line leading to one connector. The second contacts in the same four levels would all be connected to another single trunk line leading to the second connector in the group, and so on throughout all the contacts in the four levels. As shown in Fig. 1, the contacts a, b, and c are assumed to be the first contacts in the first level of the two line banks of contacts and the private bank of contacts, respectively, the contacts a b and c the first contacts in the second level, etc. The contacts 6', 6 b and b are all multipled together and connect to a. single trunk line conductor 26. Likewise, the line contacts a, a a and a are all multipled together and connected to the single conductor 27. The private bank contacts 0', 0 c and c are not multipled together, but from each private bank contact there is a separate conductor leading to the connector switch. At the connector switch ther are four relays 28, 2-9, 30 and 31. The conductors leading from selector private bank contacts 0, 0 c and 0 pass through the relays 28, 29, 30 and 31, respectively, at the connector, and are then multipled together and connected to the spring 32 of the relay 33. Each of the relays 28, 29, 30 and 31 is adapted, when energized, to connect one terminal of one of the ringing current generators R, R R and R with the spring 34 of the ringing relay 22. The other terminal of all the generators is connected to the spring 35 of the ringing relay Although the system is described as a four-party party-line system, it will be evident that it is not limited to this number. If it is desired to alter the number of substations on each line, it is only necessary to correspond 'ingly alter the number of ringing current y a pluralit of groups of connectorsthat is,

as shown erein, the first four levels might be connected to one grou of connectors having access to one group 0 subscribers lines, and the next four levels of the selector banks might be connected to another group of connectors which have access to a difierent group of lines.

Having given a general description of the apparatus, a general description of the complete operation by means of which the connection is extended from the calling to the called substation will now be given. The calling subscriber, upon removing his receiver from the switch hook, permits said hook to rise, thus bridging the talking circuit across the line conductors 36 and 37, whereby an energizing circuit is closed through the line winding 38 of the line switch C. The line switch C operates in 'response to the energization of its line relay to cause its plunger to be thrust into a bank of contacts to cause the line circuit to be extended through the springs 39 .and 40 and 41 and 42 to a first selector E. The calling subscriber now operates his dial for the first digit of the called number in the usual manner, thereby transmitting a series of impulses through the line relay 5 of the first selector E. The first selector E operates in response to these impulses in a well-known manner to extend the connection through its wipers 43 and 44 to an idle selector E in a group which has access to the group of connectors which has access to the line of the desired subscriber. As has been explained, the connector H is accessible through four different levels of the selectors E, any one of which will serve the purpose of afi'ording a connection with said connector. If, however, the connection is extended over the first level, the ringing current generator R will be used to signal the called subscriber. If the second level is used, the ringing current generator R will be used, etc. This is accomplished in the following manner: For instance, as shown herein, the connection is extended over the first level. As soon as connection is extended to the connector its line relay 1'? becomes energized and closes .a circuit through the slow-acting release re-' lay 33. The relay 33, upon energizing, extends a guarding potential from ground G through the springs 45 and 32, back through each of the relays 28, 29, 30 and 31 to the selector private bank contacts 0, c 0 and 0 of all the selectors which have access to the trunk line 26-27, to protect said trunk line from being seized by any other selector while it is in use. Since the wipers of the selector E have been placed in contact with its contacts in the first level, there is an energizing circuit completed from ground G through the relay 28 in the connector, thence throu h the contact a rivate wi er 46,.

a a P P side sWitCh wiper 47, springs 48 and the release relay 49 in multiple with the relay 10 in the selector E to the battery lead 50, thence through battery B to ground G. it will to the particular level upon which the wiper of the selector E is resting-is energized. The relay 28, upon energizing, connects the V ringing current generator R with the ringing relay spring 34.

The calling subscriber now operates his calling device for the third digit of the called number, whereby the circuit of the connector line relay 1'? is momentarily broken a number of times, corresponding to the digit called. The relay 33 is a slow acting relay and does not deenergize during the momentary interruption of its circuit by the line relay. Thus each time the line relay deenergizes, an impulse is transmitted over the circuit extending from ground Gr through the spring 51 and its back contact, spring 52 and its front contact, vertical magnet 18, side switch wiper 53 and slow-acting private magnet'relay 54 to the battery lead 50. Each time the vertical magnet 18 is energized the switch wipers 55, 56 and 57 are raised one step. The relay 54, which is energized in series with the vertical magnet, is a slow-acting relay and remains energized during the entire time the impulses are being transmitted through it. In its energized position the relay 54 closes the circuit of the private magnet 21. l/Vhen the relay 54 deenergizes atter the last impulse is delivered to the vertical magnet, it breaks the circuit of the private magnet 21, which thereupon delinergizes and permits the side switch to pass to second position. The calling subscriber now operates his calling device for the last digit of the called number. Each time the line relay 1'? denergizes in response to the impulses for this digit, an impulse is transmitted over the circuit extending fromground G through the springs 51, 52 and 58, rotary magnet 19, side switch Wiper 53 (in second position) and relay 54 to the battery lead 50. The rotary magnet operates in response to these impulses to rotate the connector wipers onto the contacts of the called line. The slow-acting relay 54 operates in the same manner as for the previous digit to cause the private magnet 21 to move the side switch one more step (from second to third position) after the last impulse is delivered to the rotary magnet. The side switch wipers 59 and 60. upon reaching third position, complete the connection between the calling and the called lines. as outlined by the heavy conductors in the drawings. The side switch wiper 53, upon reachingthird position, completes a circuit extending from ground G through the interrupter 61, springs 62, relay 22, side switch wiper 53' and relay 54 to the battery lead. The ringing relay 22, upon energizing, disconnects the calling line from the called line and establishes a path for ringing current from one terminal of the generator R through the spring 63 of the relay 28 and its front contact 64,- thence through the ringing relay springs 34 and 65, side switch wiper 60, shaft wiper 55, thence to and through al the ringers 24 in multiple on the line and back over the other side of the line and through the connector wiper 56, side switch Wiper 59, ringing relay springs 66 and 35 to the other terminal of the generator R. Although this ringing current passes through all the ringers on the line, only that ringer which is adapted to respond to the particular frequency of ringing current produced by the generator R will be actuated. When the called subscriber removes his receiver from the switch hook in response to the call, he bridges his transmitter and receiver across the line in the usual manner, whereupon the substation is provided with talking current through the two windings of the back-brldge relay 23 of the connector. The relay 23, upon energizing, separates the springs 62 and thereby renders the ringing relay 22 inoperative.

After the conversation is completed, the entire connection is automatically released by the hanging up of the receiver at the calling substation. When the receiver at the substation A is restored to the switch hook, the circuit of the connector line relay 17 is interrupted. The relay 17, upon denergizing, opens the circuit of the relay 33. The relay 33, upon denergizing, completes the circuit of the release magnet 20. This circuit extends from ground G through the spring 51 and its back contact, spring 52 and its back contact, magnet 20 and the oil' normal springs 67, which are closed by the first vertical movement of the switch shaft, to the battery lead 50. The magnet 20, upon energizing, immediately restores the connector to normal position. The relay 33 of the connector, upon deenergizing, also destroys the holding circuits of the release relays 49 and 10 of the selectors E and E, respectively. The relays 49 and 10, upon dee'nergizing, close the circuits of their respective release magnets 68 and 9 in the same manner as explained for the magnet 20 of the connec tor. The magnets 68 and 9, upon energizing, restore their respective switches. The relay 10. upon dee'nergizing, also destroys the holding circuit for the holding winding 71 of the line switch C and permits its plunger to'be restored to normal position.

Fig. 3 shows a different manner of connecting the frequency controlling relays 28,

29, 30 and 31 from that shown in Fig. 2,

only sufficient of the circuit of the connector being shown to indicate the changes necessitated by this change 1n the connection of 70, which is connected to the line in the same manner as the upper winding of the relay 17. The private contacts 0, 0 c and c are all multipled together and connected directly to the spring 32 of the relay 33. In Fig. 3 the lower line contacts arenot multipled together, but each one is connected through a separate one of the relays 28, 29, 30 and 31 with the grounded terminal of the battery. It will thus be seen that the same result is obtained with the arrangement shown in Fig. 3 as with that shown in Fig. 2, the only difference being that the frequency controlling relay is energized by the talking current which is fed back to the calling line instead of being energized by current over the release'trunk.

While I have chosen to illustrate certain forms of my invention in connection with 95 a complete automatic system of a certain type, it is to be understood that my invention is of broader scope and is equally as well adapted to be used in connection with any other forms of automatic systems or semi-automatic systems.

What I claim as my invention is 1. In a party-line telephone system, a subscribers line, a connector for seizing said line, means for extending connection to said 1 connector, a plurality of ringing generators,

a relay for controlling each of said generators, means for energizing one of said relays upon thecompletion of the connection to the connector, a ringing relay, and means 11 for ener izing said relay upon seizure of the calle line to apply the current from the selected generator to the called line.

2. In a arty-line telephone system, a subscri'bers line, a connector for seizing said line, means for extending connection to said connector, a plurality of ringing generators,

a relay for controlling each generator, said relays being connected in parallel circuits, means for energizing one of said relays to control the associated generator upon the completion of the connection to the connector, a ringing relay, and means for energizing said relay upon seizure of the called line to apply the current from the selected generator to the called line.

3. In a party-line telephone system, a calling and a called subscribers line, a connector for seizing the called line. and means including a selector for extending connection from the callin line to said connector, said selector including a pair of line contact banks arranged in a plurality of levels, a bank of private contacts, multiple connections from corresponding line contacts in a plurality of said levels to said connector, whereby connection may be established with said connector through a plurality of said levels, and independent connections from the corresponding contacts in said private bank to said connector.

4. In a party-line telephone system, a calling and a called subscribers line, a connector for seizing the called line, and means including aselector for extending connection from the calling line to said connector, said selcctor including "a pair of line contact banks arranged in a plurality of levels, a bank of private contacts, multiple connections from corresponding line contacts in a plurality of said levels to said connector, whereby connection may be established with said connector through a plurality of said levels, independent connections from the corresponding contacts in said private bank to said connector, a plurality of ringing generators for supplying ringing current to the called line, and means controlled over said independent connections for selecting one of said ringing generators.

5. In a party-line telephone system, a calling and a called subscribers line, a connector for seizing the called line, and means including a selector for extending connection from the calling line to said connector, said selector including a pair of line contact banks arranged in a plurality of levels, a bank of private contacts, multiple connections from corresponding line contacts in a plurality of said levels to said connector, whereby connection may be established with said connector through a plurality of said levels, independent connections from' the corresponding contacts in said private bank to said connector, a plurality of ringing generators in said connector for supplying ringing current to the called line, a relay in each of said independent connections for controlling the selection of one of said generators, and means for energizing one of said relays when connection is made with said connector, the relay energized belng dependent upon the level of the selector switch employed in extending the connection.

6. In a party-line telephone system, subscribers lines divided into groups, a connector having motion in one plane to select groups and motion in a plane at rightangles thereto to finda line in the selected group for seizing a called sulbscribers line, means for extending connection to said connector, a plurality'of ringing generators, a relay for controlling each of said generators, means for energizing one of said relays upon the completion of the connection to the connector, a ringing relay, and means for energizing said relay upon seizure of the called line to apply the current from the selected generator to the called line.-

7. In a party-line telephone system, subscribers lines divided into groups, a connector having motion in one plane \to select groups and motion in a plane at right-angles thereto to find a line in the selected group for seizing a called subscribers line, means for extending connection to said connector, a plurality of ringing generators, a relay for controlling each generator, said relays being connected in parallel circuits, means for energizing one of said relays to control the associated generator upon the completion of the connection to the connector, a ringing relay, and means for energizing said relay upon seizure of the called line to apply the current from the selected generator to the called line.

8. In a party-line telephone system, a called line, a connector for seizing said line, a line relay for said connector energized when connection is extended to said. connector, a second relay controlled by said line relay, a plurality of ringing generators for supplying current to the called line, a series of relays for selecting one of said ringing generators, and a circuit for said last-men tioned relays controlled by said second relay.

9. In a party-line telephone system, a called line, a connector for seizing said line, a line relay for said connector energized when connection is extended to said connector, a slow-acting relay controlled by said tion from the calling line to said connector,

said selector including a bank of contacts divided into levels, connections from corre sponding contacts on a plurality of said levels to said connector, a line relay .for said connector, a second relay controlled by said line relay, a plurality of ringing generators, a relay for each generator for controlling the selection of said ringing generators, parallel circuits for said last-mentioned relays controlled by said second relay, and means for energizing one of said generator-controllingrelays upon connection being made with said connector, the relay energized de ending upon the level of the selector emp oyed in extending connection to the connectorf 11. In a telephone system, two trunk lines of difl'erent character both terminating in the same connector switch, said switch having different operating functions characteristic of the different trunk lines, a test conductor associated with each trunk line, and a relay in series with one of said test conductors and controllable thereover, said relay when 0 erated serving to alter certain operating circuits of said switch.

12. In a telephone system, two trunk lines of diflerent character both terminating in the same connector switch, said switch having different ringing and talking circuits characteristic of the different trunk lines, a test conductor associated with each trunk line, and a relay in series with one of said test conductors and controllable thereover, said relay when operated efiective to alter the'said circuits.

13. In an automatic telephone system having a two-party line, means for ringing each station on the two-party line from a single connector, said means comprising said single connector, a ringing relay on said single connector, and means for switching a generator current connection on said ringing relay, said lastnamed means embodying a switching relay and a selector, a side switch disposed on said selector, a battery having one terminal connected to said switching relay and the other terminal connected to said side switch.

14. In an automatic telephone system having a two-party line, means for ringing either station on the two-party line from a single connector, said means comprising said single connector, a ringing relay on said single connector, and means for switching a generator current connection on said ringing relay, said last-named means embodying a switching relay and a selector, a side switch disposed on said selector, a battery having one terminal connected to said switching relay and the other terminal connected to said side switch, and a wiper on said selector connecting said side switch to'a bank contact.

15. In an automatic telephone system having a two-party line, means for ringing either station on the two-party line from a single connector, said means comprising said single connector, a ringing relay on said single connector, and means for switching a generator current connection on said ringing relay, said last-named means embodying a switching relay and a selector, a side switch disposed on said select-or, a battery having one terminal connected to said switching relay and the other terminal connected to said side switch, a wiper on said selector connecting said side switch to a bank contact, and means connecting said bank contact to said switching relay.

Signed by me at Chicago, Cook county, Illinois, this 20th day of January, 1912.

' MICHAEL SCHWARTZ.

Witnesses:

ARTHUR J. RAY, ALBERT ANDERSEN. 

